Proteins Flashcards

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1
Q

What are proteins important for?

A

-enzymes-antibiotics-haemoglobin-hormones eg insulin-receptors and channels-structure (muscles)-cytoskeleton -keratin (hair and nails)

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2
Q

What are polymers made out of?

A

Monomers called amino acids.

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3
Q

How many amino acids are there?

A

20 in total

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4
Q

What are amino acids made of?

A

C,H,O,N and sometimes S

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5
Q

How are amino acids joined?

A

By peptide bonds.

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6
Q

Two amino acids joined are called…

A

Dipeptide

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7
Q

More than two amino acids joined are called…

A

polypeptide

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8
Q

One or more polypeptides are called…

A

A protein

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9
Q

What varies about the structure of the amino acids?

A

Have the same basic structure but have a variable R group.

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10
Q

What is the structure of a basic amino acid?

A

See Notes

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11
Q

How are dipeptides and polypeptides formed and broken down?

A

Formed by condensation reactions and broken down by hydrolysis reactions.

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12
Q

How many levels are there in protein structure?

A

4

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13
Q

Do all proteins have all 4 structures?

A

They all have the first 3 and only some have the fourth.

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14
Q

What are the 4 structures?

A

-Primary Structure-Secondary Structure-Tertiary Structure-Quaternary Structure

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15
Q

What is the Primary Structure?

A

The sequence of amino acids that make up the polypeptide chain.

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16
Q

In the Primary Structure, what could happen if an amino acid changed?

A

Could affect the whole protein.

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17
Q

What is the Secondary Structure?

A

Where the polypeptide chain folds into an alpha helix or a beta pleated sheet.

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18
Q

Why does this folding happen in the Secondary Structure?

A

Because the -NH and the -CO groups are polar so hydrogen bonds form between them.

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19
Q

What is the Tertiary Structure?

A

Where the alpha helix or beta pleated sheet folds further due to additional bonding between nearby R-groups.

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20
Q

What are the 4 type of bonds in the tertiary structure?

A

-Disulphide Bridge
-Ionic Bonds
-Hydrogen Bonds
-Hydrophobic /Hydrophilic interactions

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21
Q

Where are the Disulphide bridge bonds in the tertiary structure?

A

Between sulphur atoms in nearby cytosines.

22
Q

Where are the Ionic bonds in the tertiary structure?

A

Between - and + R groups.

23
Q

Where are the Hydrogen bonds in the tertiary structure?

A

Between S+ hydrogens and S- atoms in nearby R groups.

24
Q

Where are the Hydrophilic/Hydrophobic interactions the tertiary structure?

A

Hydrophobic R groups-insideHydrophilic R groups-outside

25
Q

What is the Quaternary Structure?

A

Where several polypeptide chains join together.

26
Q

How are these several polypeptide chains held together in the quaternary structure?

A

Held together by the same bonds found in the tertiary structure.

27
Q

What are the 2 types of protiens?

A

Globular and Fibrous

28
Q

What is the structure of Globular Proteins and how is this formed?

A

Round, Compact structure due to hydrophobic and hydrophilic interactions.

29
Q

Why are Globular Proteins Soluble?

A

The hydrophilic parts are on the outside so they’re easily transported in fluid.

30
Q

What are the 3 examples of Globular Proteins?

A

-Amylase
-Insulin
-Haemoglobin

31
Q

What is Amylase made from? And what does it beak down into?

A

A single polypeptide chain and breaks down into maltose.

32
Q

What does the secondary structure of Amylase consist of?

A

Alpha helix and beta pleated sheets which then fold up into a Globular Protein.

33
Q

What is Insulin?

A

Produced by the pancreas and helps to regulate blood-glucose levels.

34
Q

What is Insulin made from?

A

2 polypeptide chains (a dimer) held together by two disulphide.

35
Q

What is Insulin stored as?

A

A hexamer (a globular protein) due to hydrophobic/hydrophilic interactions between the dimers.

36
Q

What is Haemoglobin made out of?

A

4 polypeptide chains-2 alpha chains and 2 beta chains (in adults). Each chain is globular.

37
Q

What type of proteins are the polypeptides made from?

A

Conjugated proteins.

38
Q

What are conjugated Proteins?

A

Proteins with a prosthetic (non-protein) group attached to them.

39
Q

How many prosthetic groups does haemoglobin have and what is its name?

A

4 prosthetic groups called haem.

40
Q

What do each of the prosthetic groups contain?

A

One iron atom which can bind to one molecule of O2.

41
Q

What is the structure and characteristics of Fibrous Proteins?

A

-Structural Proteins
-Long, strong, tough and rope shaped.
-Insoluble, non-polar and unreactive.

42
Q

What are 3 examples of Fibrous Proteins?

A

-Collagen
-Keratin
-Elastin

43
Q

What is Collagen?

A

A very strong protein fibril which is flexible but doesn’t stretch.

44
Q

Where is Collagen found?

A

Skin, bone, blood vesicles, muscles, ligaments, tendons and cartilage.

45
Q

What is Collagen made out of and what structure is it in?

A

3 polypeptide chains arranged in a triple helix, held together by hydrogen bonds.

46
Q

Where is Keratin found?

A

In the external structure of many animals.

47
Q

What are the 2 characteristics of Keratin?

A

Can be tough or flexible

48
Q

Where is Elastin found?

A

Connective tissue of the skin, lungs, bladder, arteries and some ligaments

49
Q

How do you test for a protein?

A

1)Add some sodium hydroxide solution and shake.
2)Then add some dilute copper sulphate solution.
3)If pale blue colour turns purple there is a protein present.

50
Q

What are we really testing for when we test for a protein?

A

The peptide bond

51
Q

What could be used instead of using sodium hydroxide and then dilute copper sulphate?

A

Biurets as they contain both of these.